Devices and methods for intracardiac procedures

ABSTRACT

The invention provides devices and methods for performing less-invasive surgical procedures within an organ or vessel. In an exemplary embodiment, the invention provides a method of closed-chest surgical intervention within an internal cavity of a patient&#39;s heart or great vessel. According to the method, the patient&#39;s heart is arrested and cardiopulmonary bypass is established. A scope extending through a percutaneous intercostal penetration in the patient&#39;s chest is used to view an internal portion of the patient&#39;s chest. An internal penetration is formed in a wall of the heart or great vessel using cutting means introduced through a percutaneous penetration in an intercostal space in the patient&#39;s chest. An interventional tool is then introduced, usually through a cannula positioned in a percutaneous intercostal penetration. The interventional tool is inserted through the internal penetration in the heart or great vessel to perform a surgical procedure within the internal cavity under visualization by means of the scope. In a preferred embodiment, a cutting tool is introduced into the patient&#39;s left atrium from a right portion of the patient&#39;s chest to remove the patient&#39;s mitral valve. A replacement valve is then introduced through an intercostal space in the right portion of the chest and through the internal penetration in the heart, and the replacement valve is attached in the mitral valve position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of commonly-assigned,co-pending application Ser. No. 08/163,241, filed Dec. 6, 1993now U.S.Pat. No. 5,571,215, which is a continuation-in-part of application Ser.No. 08/023,778, filed Feb. 22, 1993now U.S. Pat. No. 5,452,733. Thisapplication is also a continuation-in-part of copending application Ser.No. 08/159,815, filed Nov. 30, 1993, now U.S. Pat. No. 5,433,700, nowU.S. Pat. No. 5,433,700 which is a U.S. counterpart of Australian PatentApplication No. PL 6170, filed Dec. 3, 1992. The complete disclosures ofall of these applications are hereby incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to instruments and techniques forperforming less-invasive surgical procedures, and more specifically, toinstruments and techniques for less-invasive surgery within the heartand great vessels.

BACKGROUND OF THE INVENTION

Various types of surgical procedures are currently performed toinvestigate, diagnose, and treat diseases of the heart and the greatvessels of the thorax. Such procedures include repair and replacement ofmitral, aortic, and other heart valves, repair of atrial and ventricularseptal defects, pulmonary thrombectomy, treatment of aneurysms,electrophysiological mapping and ablation of the myocardium, and otherprocedures in which interventional devices are introduced into theinterior of the heart or a great vessel.

Using current techniques, many of these procedures require a grossthoracotomy, usually in the form of a median sternotomy, to gain accessinto the patient's thoracic cavity. A saw or other cutting instrument isused to cut the sternum longitudinally, allowing two opposing halves ofthe anterior or ventral portion of the rib cage to be spread apart. Alarge opening into the thoracic cavity is thus created, through whichthe surgical team may directly visualize and operate upon the heart andother thoracic contents.

Surgical intervention within the heart generally requires isolation ofthe heart and coronary blood vessels from the remainder of the arterialsystem, and arrest of cardiac function. Usually, the heart is isolatedfrom the arterial system by introducing an external aortic cross-clampthrough a sternotomy and applying it to the aorta between thebrachiocephalic artery and the coronary ostia. Cardioplegic fluid isthen injected into the coronary arteries, either directly into thecoronary ostia or through a puncture in the aortic root, so as to arrestcardiac function. In some cases, cardioplegic fluid is injected into thecoronary sinus for retrograde perfusion of the myocardium. The patientis placed on cardiopulmonary bypass to maintain peripheral circulationof oxygenated blood.

Of particular interest to the present invention are intracardiacprocedures for surgical treatment of heart valves, especially the mitraland aortic valves. According to recent estimates, more than 79,000patients are diagnosed with aortic and mitral valve disease in U.S.hospitals each year. More than 49,000 mitral valve or aortic valvereplacement procedures are performed annually in the U.S., along with asignificant number of heart valve repair procedures.

Various surgical techniques may be used to repair a diseased or damagedvalve, including annuloplasty (contracting the valve annulus),quadrangular resection (narrowing the valve leaflets), commissurotomy(cutting the valve commissures to separate the valve leaflets),shortening mitral or tricuspid valve chordae tendonae, reattachment ofsevered mitral or tricuspid valve chordae tendonae or papillary muscletissue, and decalcification of valve and annulus tissue. Alternatively,the valve may be replaced, by excising the valve leaflets of the naturalvalve, and securing a replacement valve in the valve position, usuallyby suturing the replacement valve to the natural valve annulus. Varioustypes of replacement valves are in current use, including mechanical andbiological prostheses, homografts, and allografts, as described inBodnar and Frater, Replacement Cardiac Valves 1-357 (1991), which isincorporated herein by reference. A comprehensive discussion of heartvalve diseases and the surgical treatment thereof is found in Kirklinand Barratt-Boyes, Cardiac Surgery 323-459 (1986), the completedisclosure of which is incorporated herein by reference.

The mitral valve, located between the left atrium and left ventricle ofthe heart, is most easily reached through the wall of the left atrium,which normally resides on the posterior side of the heart, opposite theside of the heart that is exposed by a median sternotomy. Therefore, toaccess the mitral valve via a sternotomy, the heart is rotated to bringthe left atrium into an anterior position accessible through thesternotomy. An opening, or atriotomy, is then made in the right side ofthe left atrium, anterior to the right pulmonary veins. The atriotomy isretracted by means of sutures or a retraction device, exposing themitral valve directly posterior to the atriotomy. One of theforementioned techniques may then be used to repair or replace thevalve.

An alternative technique for mitral valve access may be used when amedian sternotomy and/or rotational manipulation of the heart areundesirable. In this technique, a large incision is made in the rightlateral side of the chest, usually in the region of the fifthintercostal space. One or more ribs may be removed from the patient, andother ribs near the incision are retracted outward to create a largeopening into the thoracic cavity. The left atrium is then exposed on theposterior side of the heart, and an atriotomy is formed in the wall ofthe left atrium, through which the mitral valve may be accessed forrepair or replacement.

Using such open-chest techniques, the large opening provided by a mediansternotomy or right thoracotomy enables the surgeon to see the mitralvalve directly through the left atriotomy, and to position his or herhands within the thoracic cavity in close proximity to the exterior ofthe heart for manipulation of surgical instruments, removal of excisedtissue, and/or introduction of a replacement valve through the atriotomyfor attachment within the heart. However, these invasive, open-chestprocedures produce a high degree of trauma, a significant risk ofcomplications, an extended hospital stay, and a painful recovery periodfor the patient. Moreover, while heart valve surgery produces beneficialresults for many patients, numerous others who might benefit from suchsurgery are unable or unwilling to undergo the trauma and risks ofcurrent techniques.

What is needed, therefore, are devices and methods for carrying outheart valve repair and replacement as well as other procedures withinthe heart and great vessels that reduce the trauma, risks, recovery timeand pain that accompany current techniques. The devices and methodsshould facilitate surgical intervention within the heart or greatvessels without the need for a gross thoracotomy, preferably throughsmall incisions within intercostal spaces of the rib cage, withoutcutting, removing, or significantly deflecting the patient's ribs orsternum. In particular, the devices and methods should allow for removalof tissue from the thoracic cavity, as well as for introduction ofsurgical instruments, visualization devices, replacement valves and thelike into the thoracic cavity, to facilitate heart valve repair andreplacement. Preferably, the devices and methods should facilitatereplacement of a heart valve with various types of prostheses, includingmechanical and biological prostheses, homografts, and allografts.

SUMMARY OF THE INVENTION

The invention provides devices and methods for performing less-invasivesurgical procedures within an organ or vessel, and particularly, withinthe heart and great vessels of the thoracic cavity. The devices andmethods of the invention facilitate intervention within the heart orgreat vessels without the need for a median sternotomy or other form ofgross thoracotomy, substantially reducing trauma, risk of complication,recovery time, and pain for the patient. Using the devices and methodsof the invention, surgical procedures may be performed throughpercutaneous penetrations within intercostal spaces of the patient's ribcage, without cutting, removing, or significantly displacing any of thepatient's ribs or sternum. The devices and methods are particularlywell-adapted for heart valve repair and replacement, facilitatingvisualization within the patient's thoracic cavity, repair or removal ofthe patient's natural valve, and, if necessary, attachment of areplacement valve in the natural valve position. The inventionfacilitates valve replacement with any of a variety ofcommercially-available replacement valves, including mechanicalprostheses, bioprostheses, homografts, and allografts.

In a first preferred embodiment, the invention provides a method ofclosed-chest surgical intervention within an internal cavity of thepatient's heart or great vessel. Utilizing the method of the invention,the patient's heart is arrested and cardiopulmonary bypass isestablished. An internal portion of the patient's chest is viewed bymeans of a scope extending through a percutaneous intercostalpenetration in the patient's chest. A cutting means is introducedthrough a percutaneous intercostal penetration in the patient's chest,and the cutting means is used to form an internal penetration in a wallof the heart or great vessel. An interventional tool is then introducedthrough a percutaneous intercostal penetration and through the internalpenetration in the heart or great vessel to perform a surgical procedurewithin the internal cavity under visualization by means of the scope.One or more percutaneous cannulae may be positioned within anintercostal space of the chest wall through which the interventionaltool may be introduced into the chest cavity. The surgical procedureswhich may be performed within the heart or great vessel include repairor replacement of heart valves, repair of atrial and ventricular septaldefects, pulmonary thrombectomy, treatment of aneurysms,electrophysiological mapping and ablation of the myocardium, myocardialdrilling, correction of congenital defects, coronary artery bypassgrafting, and other procedures.

The patient's heart is preferably arrested by occluding the patient'saorta between the patient's coronary arteries and the patient'sbrachiocephalic artery with an expandable member on a distal end of anendovascular catheter. Cardioplegic fluid is then introduced through alumen in the catheter into the patient's aorta upstream of theexpandable member to arrest cardiac function. Alternatively, or inaddition to such antegrade cardioplegic fluid delivery, cardioplegicfluid may be delivered in a retrograde manner by means of a catheterpositioned in the coronary sinus of the patient's heart. In analternative approach, an external cross-clamp may be placedthoracoscopically on the aorta through a small incision or cannula inthe patient's chest. Cardioplegic fluid may be delivered through eithera thoracoscopically introduced cannula or an endovascular catheterextending into the ascending aorta upstream of the cross-clamp.

In one aspect the present invention consists in a method for inducingcardioplegic arrest of a heart in situ in a patient's body, comprisingthe steps of:

(a) maintaining systemic circulation with peripheral cardiopulmonarybypass;

(b) occluding the ascending aorta through a percutaneously placedarterial balloon catheter;

(c) introducing a cardioplegic agent into the coronary circulation; and

(d) venting the left side of the heart.

The method according to the present invention may be carried out onhumans or other mammalian animals. The method is of particularapplicability in humans as it allows an alternative approach to openheart surgery and the development of closed cardioscopic surgery. Themethod according to the invention enables a percutaneous by-pass systemto be associated with cardioplegia, venting and cooling of the heartwhich subverts the need for median sternotomy. This may, in turn, reducethe complications of the surgery.

The maintenance of the systemic circulation involves establishing acardiopulmonary by-pass. The blood may be drawn into the by-pass merelyby positioning a percutaneous catheter into the right atrium and/or intoone or both of the vena cavae through which venous blood may be drawnfrom the heart into an extracorporeal pump oxygenator. In more preferredembodiments of the invention a single catheter with two inflatablecuffs, or two separate catheters, each with an inflatable cuff areintroduced into the vena cavae to occlude them adjacent to their rightatrial inlets. This allows isolation of the right atrium and allowsblood to be drawn from the vena cavae into the by-pass system. There isalso preferably provision for percutaneous communication via onecatheter with the right atrium to allow infusion of saline into theright atrium. This infusion has the advantage that it allows the heartto be cooled and improves visual acuity within the right heart allowingdirect cardioscopic examination and/or intervention.

The catheter used to decompress the right atrium and to draw blood intothe bypass is preferably introduced through the femoral vein bypercutaneous puncture or direct cut down. If other than simple venousdrainage is required catheters with inflatable cuffs, as describedabove, are placed preferably such that in inflatable cuff of the cannulais positioned within each of the inferior (suprahepatic) and superiorvena cavae. There is preferably a lumen in the cannula acting as acommon blood outlet from the vena cavae leading to the pump oxygenator.A separate lumen is preferably used to infuse saline between the twoinflated cuffs into the right atrium. If, alternatively, separatecatheters are used to occlude each of the inferior and superior venacavae than the cannula for the inferior vena cavae is preferablyintroduced percutaneously from the femoral vein and that for thesuperior vena cavae is introduced percutaneously through the jugular orsubclavian vein.

The ascending aorta is preferably occluded by a balloon catheterintroduced percutaneously through the femoral artery. This catheter mustcarry adjacent its tip an inflatable cuff or balloon of sufficient sizethat upon being inflated it is able to completely occlude the ascendingaorta. The length of the balloon should preferably not be so long as toimpede the flow of blood or other solution to the coronary arteries orto the brachiocephalic, left carotid or left subclavian arteries. Aballoon length of about 40 mm and diameter of about 35 mm is suitable inhumans. The balloon is of a cylindrical shape to fully and evenlyaccommodate the lumen of the ascending aorta. This maximizes the surfacearea contact with the aorta, and allows for even distribution ofocclusive pressure.

The balloon of the catheter is preferably inflated with a salinesolution to avoid the possibility of introducing into the patient an airembolism in the event that the balloon ruptured. The balloon should beinflated to a pressure sufficient to prevent regurgitation of blood intothe aortic root and to prevent migration of the balloon into the rootwhilst not being so high as to cause damage or dilation to the aorticwall. An intermediate pressure of the order of 350 mmHg has been proveneffective in trials.

The aortic catheter is preferably introduced under fluoroscopic guidanceover a suitable guidewire. Transoesophageal echocardiography canalternatively be used for positioning as has been described withreference to the venous catheter. The catheter may serve a number ofseparate functions and the number of lumina in the catheter will dependupon how many of those functions the catheter is to serve. The cathetercan be used to introduce the cardioplegic agent, normally in solution,into the aortic root via one lumen. The luminal diameter will preferablybe such that a flow of the order of 250-500 ml/min of cardioplegicsolution can be introduced into the aortic root under positive pressureto perfuse adequately the heart by way of the coronary arteries. Thesame lumen can, by applying negative pressure to the lumen from anoutside source, effectively vent the left heart of blood or othersolutions. It may also be desirable to introduce medical instrumentsand/or a cardioscope into the heart through another lumen in thecatheter. The lumen should be of a diameter suitable to pass afibre-optic light camera of no greater than 3 mm diameter. It ishowever, preferable that the diameter and cross-sectional design of theinternal lumina is such that the external diameter of the catheter inits entirety is small enough to allow its introduction into the adultfemoral artery by either percutaneous puncture or direct cut-down.

The oxygenated blood returning to the body from the by-pass system maybe conveyed into the aorta from another lumen in the cannula carryingthe balloon. In this case the returning blood is preferably discardedfrom the catheter in the external iliac artery. In another embodiment ofthe invention, and in order to reduce the diameter of the cathetercarrying the balloon, a separate arterial catheter of known type may beused to return blood to the patient from the by-pass system. In thiscase a short catheter is positioned in the other femoral artery toprovide systemic arterial blood from the bypass system. The control endof the catheter, i.e. that end that remains outside of the body, shouldhave separate ports of attachment for the lumina. The catheter lengthshould be approximately 900 mm for use in humans.

The cardioplegic agent may be any of the known materials previouslyknown to be useful, or in the future found to be useful, as cardioplegicagents. The agent is preferably infused as a solution into the aorticroot through one of the lumina of the aortic catheter.

In another aspect the present invention consists in a catheter for usein occluding the ascending aorta comprising an elongate tube having oneor more continuous lumina along its length, an inflatable cuff isdisposed about the tube adjacent one end thereof, the cuff being of sucha size that upon being inflated it is able to occlude the ascendingaorta of a patient.

The invention thus contemplates, at least in its preferred embodiments,the possibility of effective ascending aortic occlusion, cardioplegia,venting, right heart deflation and topical cooling in association withextracorporeal cardiopulmonary bypass all without necessitating a mediansternotomy or other thoracic incision.

The catheter and method used to induce cardioplegic arrest may be usedin a number of surgical procedures. These include the following:

(1) Coronary artery revascularization such as:

(a) angioscopic laser introduction or angioscopic balloon angioplastycatheter into the coronary arteries via one lumen of the aorticcatheter; or

(b) thoracoscopic dissection of one or both of the mammary arteries withrevascularization achieved by distal anastomoses of the internal mammaryarteries to coronary arteries via a small left anterior thoracotomy.

(2) Secundum - type atrial septal defect repair such as by:

(a) “Closed” cardioscopic closure, or

(b) Closure as an “open” procedure via a mini-right thoracotomy.

(3) Sinus venosus defect repairs similar to 2 above.

(4) Infundibular stenosis relief by cardioscopic techniques.

(5) Pulmonary valvular stenosis relief by cardioscopic techniques.

(6) Mitral valve surgery via a small right thoracotomy.

(7) Aortic stenosis relief by the introduction of instrumentation via alumen in the aortic catheter into the aortic root.

(8) Left ventricular aneurysm repair via a small left anteriorthoracotomy.

In a preferred embodiment, the surgical procedure comprises surgicallytreating a heart valve. Such surgical treatment may involve repairingthe valve by introducing instruments through an intercostal penetrationand through the internal penetration in the heart to perform, forexample, annuloplasty, quadrangular resection of valve leaflets,commissurotomy, reattachment of chordae tendonae or papillary muscletissue, shortening of chordae tendonae, decalcification, and the like.

The heart valve may also be replaced with a replacement valve. In thisembodiment, the method may further comprise the step of removing all orpart of the patient's natural heart valve by means of a cutting toolintroduced through a percutaneous intercostal penetration and throughthe internal penetration in the heart. The method further comprises thestep of introducing a replacement valve through a percutaneousintercostal penetration and through the internal penetration into theinternal cavity within the heart. The replacement valve is then fastenedwithin the heart, usually by means of an instrument introduced through apercutaneous intercostal penetration and through the internalpenetration in the heart wall.

The method may further include the step of sizing the patient's heartvalve before the replacement valve is introduced. In an exemplaryembodiment, a sizing instrument is introduced through a percutaneousintercostal penetration and through the internal penetration in theheart to measure the size of the valve annulus and to determine the sizeof the replacement valve.

The replacement valve may be fastened in position in various ways,including suturing the replacement valve to an annulus at the naturalvalve position in the heart. In one embodiment, the sutures are appliedto the annulus at the valve position, drawn out of the patient's bodythrough the internal penetration and through a percutaneous intercostalpenetration, and then applied to the replacement valve. The sutures mayfurther be radially arranged in spaced-apart locations about anorganizer ring disposed outside of the patient's body. The sutures arethen held in tension as the replacement valve is introduced into theinterior of the heart and positioned in the natural valve position. Thereplacement valve may be introduced by means of a valve holder attachedto an elongated handle, or simply pushed along the sutures by means ofthe surgeon's hands or conventional tools such as forceps or needledrivers.

In a particular preferred embodiment, the heart valve comprises a mitralvalve which is disposed between the left atrium and left ventricle ofthe patient's heart. A percutaneous penetration is made within anintercostal space in a right lateral portion of the patient's chest,usually within the fourth, fifth, or sixth intercostal space. From thispenetration, an internal penetration may be formed in the wall of theleft atrium at a location which is in a generally straight line drawnfrom the penetration in the right lateral portion of the chest to thepatient's mitral valve. In this way, surgical instruments may beintroduced from the penetration in the right chest to form the internalpenetration in the heart wall, repair or excise the patient's naturalvalve, and introduce and attach a replacement valve.

In a further aspect of the invention, a prosthesis assembly is providedfor closed-chest replacement of a heart valve. The prosthesis assemblycomprises a replacement valve having an annular attachment portion and amovable valve portion coupled to the attachment portion. The prosthesisassembly further includes holder means releasably mounted to theattachment portion, wherein the holder means is configured to allowintroduction of the replacement valve through an intercostal space inthe patient's chest.

In a preferred embodiment, the replacement valve and the holder meanstogether have a profile with a width which is less than the width of theintercostal space. Preferably, the intercostal space is less than about20 mm in width. The attachment portion of the replacement valve willusually have an outer diameter which is greater than the intercostalwidth.

The holder means of the device preferably comprises an elongated handlehaving a distal end mounted to the replacement valve and a proximal endopposite the distal end. The handle is configured to introduce thereplacement valve into the patient's heart through the intercostalspace. Preferably, the handle is at least about 20 cm in length to allowpositioning the replacement valve in the heart from a right lateralportion of the patient's chest. The handle may further include means forreleasing the replacement valve, the releasing means being configuredfor actuation from the proximal end of the handle.

The handle may also include means for pivoting the replacement valvefrom a first orientation for introduction through the intercostal spaceto a second orientation for attachment in the patient's heart. Thepivoting means is configured for actuation from a proximal end of thehandle. In this way, the replacement valve may be introduced edge-firstthrough the intercostal space, then pivoted about an axis generallyperpendicular to the handle into an orientation suitable for attachmentwithin the patient's heart. Alternatively, the valve prosthesis may becollapsible or compressible to permit introduction through anintercostal space into the thoracic cavity.

Preferably, the replacement valve is premounted to the holder means andthe two are sterilized and packaged together in a sterile pack. In thisway, the pack may be opened in the sterile operating room environmentwith the valve and holder ready for immediate surgical use.

In a further embodiment, the invention provides a thoracoscopic devicefor placement of a replacement valve in a valve position of a patient'sheart. In a preferred embodiment, the thoracoscopic device comprises anelongated handle configured for positioning through an intercostal spacein the patient's chest, as described above. The device includes means ata distal end of the handle for releasably holding a replacement valve inan orientation for introduction through the intercostal space, and mayfurther include means for pivoting the replacement valve relative to thehandle from a first orientation for introduction through the intercostalspace, to a second orientation for placement in the valve position. Thethoracoscopic device further includes, in a preferred embodiment, meansat the proximal end of the handle for releasing the replacement valvefrom the holding means once the prosthesis has been positioned andsecured within the heart.

In a further aspect of the invention, a percutaneous access cannula isprovided to facilitate closed-chest replacement of a heart valve in apatient's heart. The access cannula comprises a cannula body configuredfor placement in an intercostal space in the patient's chest, thecannula having a distal end, a proximal end, and a lumen extendingtherebetween. The lumen is configured to allow passage of a replacementvalve therethrough. An obturator is positionable in the lumen tofacilitate introduction of the cannula body. The obturator has across-sectional width that is equal to or less than the width of theintercostal space, and a cross-sectional height that is greater than thecross-sectional width.

The replacement valve has an annular attachment portion with an outerdiameter, and the obturator as well as the lumen in the cannula have across-sectional height at least equal to the outer diameter, allowingthe replacement valve to be introduced through the lumen of the cannula.In one embodiment, the cross-sectional height of the lumen in thecannula is about two to six times the cross-sectional width. The lumenand obturator may have a rectangular cross-section, oval cross-section,or other shape. The cannula body may be rigid or deformable, while theobturator is usually rigid to facilitate introduction.

The access cannula may further be provided with suture retaining meanson its proximal end configured to retain a plurality of sutures in aspaced-apart relationship. The suture retaining means may have variousconfigurations, such as a plurality of slots in a proximal end of thecannula body in circumferentially spaced positions around the lumen. Theslots in the access cannula may further include means such as slitted,elastomeric inserts, for frictionally engaging the sutures to maintaintension thereon while the prosthesis is introduced into the heart.

A second organizing ring may also be provided in a position spaced-apartfrom the access cannula outside of the patient's body. The secondorganizing ring has an interior passage through which the sutures mayextend and a plurality of means circumferentially spaced around thepassage for frictionally engaging the sutures. In this way, sutures maybe applied to the valve annulus in the patient's heart, drawn throughthe lumen in the cannula and retained in the suture organizing means onthe access cannula's proximal end. The sutures may then be applied tothe replacement valve and retained in the second organizing ring. Onceall of the sutures have been applied to the prosthesis, the prosthesismay be introduced into the heart by sliding it along the sutures, whichare held in tension by the second organizing ring. Alternatively, thesutures may be held in tension by individual clamps, tape,commercially-available suture organizers, or other means for exertingtraction on the free ends of each individual suture.

The invention further provides a system for closed-chest replacement ofa heart valve in a patient's heart. The system includes means forforming a percutaneous intercostal penetration in the patient's chest,and a visualization scope configured to pass through an intercostalspace in the patient's chest for viewing an internal chest cavity. Meansare also provided for arresting the patient's heart from a locationoutside of the chest cavity. A cardiopulmonary bypass system, includingmeans for delivering oxygenated blood to the patient's arterial system,is provided for maintaining peripheral circulation of oxygenated blood.Cutting means positionable through a percutaneous intercostalpenetration into the chest cavity are provided for forming an internalpenetration in a wall of the patient's heart or great vessel. The systemfurther provides interventional means positionable through apercutaneous intercostal penetration and through the internalpenetration for performing a surgical procedure within the heart orgreat vessel.

In a preferred embodiment, the means for arresting the heart comprisesan endovascular catheter having expandable means near its distal end foroccluding the patient's ascending aorta between the patient's coronaryarteries and the patient's brachiocephalic artery. The catheter furtherincludes an internal lumen for delivering cardioplegic fluid into theaorta upstream of the expandable means to perfuse the myocardium throughthe coronary arteries.

The interventional means preferably comprises means for securing areplacement valve in a valve position within the patient's heart.Usually, the replacement valve securing means comprises an elongatedhandle like that described above, having means at its distal end forreleasably holding a replacement valve. The handle may also facilitatepivoting the replacement valve for introduction through an intercostalspace.

Preferably, the system also includes at least one cannula positionablein a percutaneous intercostal penetration, through which surgicalinstruments or a replacement valve may be introduced into the thoraciccavity. The cannula may have a lumen with a cross-sectional heightgreater than its width to allow edge-first introduction of a replacementvalve that has an outer diameter larger than the intercostal space, asdescribed above.

The system may further include cutting means positionable through apercutaneous intercostal penetration and through the internalpenetration in the patient's heart for removing at least a portion ofthe patient's heart valve. The cutting means for removing the heartvalve may comprise scissors, retractable knife, biters, or the like.

The system preferably includes means positionable through a percutaneousintercostal penetration and through the internal penetration for sizingan annulus of the patient's heart valve. In one embodiment, the sizingmeans comprises an elongated shaft and a plurality of interchangeablesizing disks of various sizes attachable to a distal end of the shaft.The shaft and sizing disk may be introduced through a percutaneousintercostal penetration and through the internal penetration to positionthe sizing disk adjacent to the annulus of the patient's heart valve,allowing a comparison of the annulus diameter to the disk diameter. Thesizing disk may be pivotable relative to the shaft to allow introductioninto the thoracic cavity through an intercostal space. Alternative meansfor sizing may also be used, such as expandable baskets, balloons,endoscopic or endovascular visualization, fluoroscopy, ortransesophageal echocardiography.

The system may further include means for attaching the replacement valveto the patient's heart, which comprises, in one embodiment, means forsuturing the replacement valve to a valve annulus in the patient'sheart. The system preferably includes organizing means for maintainingthe sutures in spaced-apart positions outside of the chest cavity afterthe sutures have been applied to the valve annulus within the heart. Theorganizing means is preferably fixed to a proximal end of a cannuladisposed in a percutaneous intercostal penetration, as described above.In this way, the sutures may be applied to the natural valve annuluswithin the patient's heart, drawn out of the chest cavity through thecannula lumen, and positioned in spaced-apart positions about thecircumference of the proximal end of the cannula. Means may also beprovided for maintaining tension on the ends of the sutures after theyhave been applied to the replacement valve. This facilitates advancingthe replacement valve along the sutures, through the lumen in thecannula, and into the chest cavity.

The system may further include retraction means positionable through anintercostal space in the patient's chest for opening the internalpenetration in the wall of the heart or great vessel. The retractionmeans may comprise a collapsible rake, tethered clamp, retractionsutures, or the like.

A further understanding of the nature and advantages of the inventionmay be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a system for closed-chest mitral valvereplacement constructed in accordance with the principles of the presentinvention, showing the use of the system in a patient.

FIG. 2 is a front view of the system of FIG. 1, showing the positioningof the system in the patient's chest.

FIG. 3 is a front view of a patient's cardiovascular system illustratingthe positioning of a system for arresting the heart and establishingcardiopulmonary bypass in accordance with the principles of the presentinvention.

FIG. 4 is a top view looking into the patient's thoracic cavity througha passage of an access cannula in the system of FIG. 1, showing thecreation of an artriotomy in the patient's left atrium.

FIG. 5 is a top view looking into the patient's thoracic cavity througha passage of an access cannula in the system of FIG. 1, showing theremoval of the mitral valve leaflets.

FIG. 6 is a top view looking into the patient's thoracic cavity througha passage of an access cannula in the system of FIG. 1, showing theapplication of sutures to the mitral valve annulus.

FIG. 7 is a perspective view of the system of FIG. 1 positioned in thepatient, showing the application of sutures to a replacement valve.

FIGS. 8A-8B are transverse cross-sectional views of the system andpatient of FIG. 1 taken through the patient's thorax, showing theintroduction of the replacement valve into the left atrium and the tyingof knots in the sutures to secure the prosthesis in the patient's heart.

FIG. 9 is a top view looking into the patient's thoracic cavity througha passage of an access cannula in the system of FIG. 1, showing pushingthe knots toward the replacement valve and trimming the free ends of thesutures.

FIG. 10 is a top view looking into the patient's thoracic cavity througha passage of an access cannula in the system of FIG. 1, showing theclosure of the patient's left atrium.

FIGS. 11A-11C are perspective, front, and top views respectively of theaccess cannula in the system of FIG. 1.

FIG. 11D is a partial cut-away view taken along line 11D—11D in FIG.11C.

FIG. 12A is a side view of angled scissors in the system of FIG. 1.

FIGS. 12B-12D are side views of a distal portion of the scissors of FIG.12A showing alternative embodiments thereof.

FIG. 13 is a side view of a retractable knife in the system of FIG. 1.

FIGS. 14A-14B are side and top views, respectively, of grasping forcepsin the system of FIG. 1.

FIG. 15 is a perspective view of a left atrial retractor in the systemof FIG. 1.

FIGS. 16A-16B are side and top views, respectively, of needle drivers inthe system of FIG. 1.

FIGS. 17A-17B are top and side views, respectively, of a replacementvalve in the system of FIG. 1.

FIG. 17C is an end view of the replacement valve of FIGS. 17A-17Bpositioned in a passage of an access cannula in the system of FIG. 1.

FIG. 18 is a perspective view of a prosthesis introducer in the systemof FIG. 1.

FIG. 19A is a side view of the prosthesis introducer of FIG. 18.

FIGS. 19B-19C are bottom and side views, respectively, of a distalportion of the prosthesis introducer of FIG. 18.

FIGS. 19D-19E are top and side views, respectively, of a stationary armof the prosthesis introducer of FIG. 18.

FIGS. 19F-19G are top and side views, respectively, of a movable arm ofthe prosthesis introducer of FIG. 18.

FIG. 20A is a side partial cut-away view of the prosthesis introducer ofFIG. 18.

FIG. 20B is a top partial cut-away view of a distal portion of theprosthesis introducer of FIG. 18.

FIG. 21 is a perspective view of a sizing disk in the system of FIG. 1,positioned on the introducer of FIG. 18.

FIGS. 22, 23A and 23B are top and side views, respectively, of thesizing disk of FIG. 21.

FIGS. 23A-23B are top and side views, respectively, of the sizing diskof FIG. 21.

FIGS. 24A-24C are front, top, and side views, respectively of a sutureorganizing ring in the system of FIG. 1.

FIGS. 25A-25B are side and top views, respectively of a knot-pushingdevice in the system of FIG. 1.

FIG. 26 is a schematic partly cut-away representation of a patient'sheart having percutaneous catheters placed therein for carrying out themethod according to the present invention;

FIG. 27 is a similar view to FIG. 26 showing the aortic catheter inposition but including an angioscope and a left ventricular ventingcannula introduced into the aortic root and left ventricle respectively,via separate lumina within the aortic catheter;

FIG. 28 is a front elevational view of part of the vascular system of apatient showing, inter alia, the aortic balloon catheter positioned inthe ascending aorta via the femoral artery;

FIG. 29 is a side elevational view of the control end of the aorticcatheter according to the present invention;

FIG. 30 is a partly cut away side elevational view of the balloon end ofthe catheter of FIG. 29 in an inflated condition;

FIG. 31a is a cross-sectional view of the catheter of FIG. 29intermediate the control end and the balloon end;

FIG. 31b is an alternative cross-sectional arrangement of the lumina inthe catheter of FIG. 29;

FIG. 32 is a cross-sectional view through the balloon end of thecatheter of FIG. 29;

FIGS. 33a and 33 b show schematically two alternative arrangements tothe catheter shown in FIG. 29;

FIGS. 34a and 34 b show schematically two alternative catheterarrangements for the isolation of the right atrium and venous drainage.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

The invention provides methods and devices for performing surgicalinterventions within the heart or a great vessel such as the aorta,superior vena cava, inferior vena cava, pulmonary artery, pulmonaryvein, coronary arteries, and coronary veins, among other vessels. Whilethe specific embodiments of the invention described herein will refer tomitral valve repair and replacement, it should be understood that theinvention will be useful in performing a great variety of surgicalprocedures, including repair and replacement of aortic, tricuspid, orpulmonary valves, repair of atrial and ventricular septal defects,pulmonary thrombectomy, removal of atrial myxoma, patent foramen ovaleclosure, treatment of aneurysms, electrophysiological mapping andablation of the myocardium, myocardial drilling, coronary artery bypassgrafting, angioplasty, atherectomy, correction of congenital defects,and other procedures in which interventional devices are introduced intothe interior of the heart, coronary arteries, or great vessels.Advantageously, the invention facilitates the performance of suchprocedures through percutaneous penetrations within intercostal spacesof the rib cage, obviating the need for a median sternotomy or otherform of gross thoracotomy.

The terms “percutaneous intercostal penetration” and “intercostalpenetration” as used herein refer to a penetration, in the form or asmall cut, incision, hole, cannula, trocar sleeve, or the like, throughthe chest wall between two adjacent ribs, wherein the patient's rib cageand sternum remain substantially intact, without cutting, removing, orsignificantly displacing the ribs or sternum. These terms are intendedto distinguish a gross thoracotomy such as a median sternotomy, whereinthe sternum and/or one or more ribs are cut or removed from the ribcage, or one or more ribs are retracted significantly, to create a largeopening into the thoracic cavity. A “percutaneous intercostalpenetration” may abut or overlap the adjacent ribs between which it isformed, but the maximum width of the penetration which is available forintroduction of instruments, prostheses and the like into the thoraciccavity will be the width of the intercostal space, bounded by twoadjacent ribs in their natural, substantially undeflected positions. Itshould be understood that one or more ribs may be retracted or deflecteda small amount without departing from the scope of the invention;however, the invention specifically seeks to avoid the pain, trauma, andcomplications which result from the large deflection or cutting of theribs in conventional, open-chest techniques.

A first preferred embodiment of a system and method of closed-chestmitral valve replacement according to the invention will be describedwith reference to FIGS. 1-10. FIG. 1 illustrates a system 20 forclosed-chest valve replacement positioned in a patient P on an operatingtable T. Preferably, a wedge or block W having a top surface angled atapproximately 20° to 45° is positioned under the right side of patient Pso that the right side of the patient's body is somewhat higher than theleft side. The patient's right arm A is allowed to rotate downward torest on table T, exposing the right lateral side of the patient's chest.

The valve replacement system 20 includes an access cannula 22 positionedpercutaneously within an intercostal space between two ribs (shown inphantom) in a right lateral side of the patient's chest. Additionalthoracoscopic trocar sleeves 24 of conventional construction arepositioned within intercostal spaces in the right lateral chest inferiorand superior to access cannula 22, as well as in the right anterior (orventral) portion of the chest. An endoscope 25 of conventionalconstruction is positioned through a percutaneous intercostalpenetration into the patient's chest, usually through one of trocarsleeves 24. The distal end of endoscope 25 (shown in phantom) ispreferably configured to view at an angle between about 30° and 90°relative to the shaft of endoscope 25, to facilitate visualization ofthe heart from the right portion of the thoracic cavity. A light source(not shown) is also provided on endoscope 25 to illuminate the thoraciccavity. A video camera 26 is mounted to the proximal end of endoscope25, and is connected to a video monitor 28 for viewing the interior ofthe thoracic cavity. A first suture organizing ring 30 is mounted to aproximal end of access cannula 22. A second organizing ring 32 ismounted to a support stand 34 fixed to table T. A replacement valve 36is held at the distal end of an introducer 38 between first organizingring 30 and second organizing ring 32. Introducer 38 extends throughsecond organizing ring 32 and is supported by support stand 34.Additional instruments to be used in a procedure such as a retractor 40,as well as cutting, suturing, stapling, aspirating, irrigating and otherdevices, may be introduced through access cannula 22, trocar sleeves 24,and/or small, percutaneous incisions within intercostal spaces of therib cage.

Referring now to FIG. 2, access cannula 22 is positioned within anintercostal space I in the right lateral side of the chest, preferablyin the third, fourth, fifth, or sixth intercostal space between adjacentribs R. Additional trocar sleeves 24A, 24B are positioned withinintercostal spaces superior and inferior to access cannula 22 in theright lateral side of the chest. Access cannula 22 and trocar sleeves24A, 24B are positioned so that instruments 42 introduced through themmay be directed toward the right side of the left atrium of the heart H.A trocar sleeve 24C is positioned in an intercostal space in the rightanterior side of the chest such that endoscope 25 may be introduced toview the thoracic cavity and heart H without interfering withinstruments introduced through access cannula 22 or trocar sleeves 24A,24B. An additional trocar sleeve 24D is positioned in an intercostalspace in the anterior side of the chest just to the right of the sternumand anterior to the right lateral side of the heart H.

It will be understood to those of ordinary skill in the art that, insome cases, it may desirable to eliminate some or all of trocar sleeves24 and/or access cannula 22, and introduce instruments directly throughsmall, percutaneous intercostal incisions in the chest. Advantageously,unlike laparoscopic, arthroscopic, and other endoscopic procedures, nodistension of the chest is required using the method of the invention,so that leakage of distension fluid through percutaneous penetrations isnot of concern. Thus, either thoracoscopic trocar sleeves without fluidseals or percutaneous incisions may be utilized for instrumentintroduction into the thoracic cavity. Trocar sleeves are generallypreferred, however, in order to provide an open passage into thethoracic cavity, to protect adjacent tissue from injury resulting fromcontact with instruments, and to avoid damaging instruments, endoscopes,replacement valves, and the like when introduced into the thoraciccavity.

Referring now to FIGS. 11A-11D, access cannula 22 will be described ingreater detail. Access cannula 22 comprises a body 44 having a proximalend 46, a distal end 48, and a passage 50 extending therebetween. Body44 is configured to fit within an intercostal space I withoutsignificant deflection of adjacent ribs R, usually having a width ofless than about 20 mm. Passage 50 is configured to facilitate passage ofreplacement valve 36 therethrough. Replacement valve 36 may have avariety of configurations, but must have a diameter at least equal tothat of the patient's natural heart valve, a diameter which commonlyexceeds the width of the intercostal spaces in the rib cage. Therefore,in order to avoid cutting or retracting the patient's ribs, replacementvalve 36 is introduced edge-first through passage 50 of access cannula22, as described more fully below. To accommodate such introduction ofreplacement valve 36, passage 50 usually has a cross-sectional width wof about 12 mm to 20 mm, and a cross-sectional height h that is somewhatgreater than cross-sectional width w, usually 2-6 times cross-sectionalwidth w, and preferably in the range of 25 mm to 50 mm. Passage 50 mayhave various cross-sectional shapes, including oval, rectangular,race-track, and the like. This accommodates a variety of replacementheart valves, including mechanical and biological prostheses, as well ashomograft and allograft tissue valves. It will be understood, however,that certain replacement valves may be collapsible or sufficiently smallin size so that passage 50 in access cannula 22 may have a round orsquare cross-section and still allow passage of the replacement valvetherethrough. However, a cross-sectional shape in which the height isgreater than the width may still be advantageous to allow greaterfreedom of movement in manipulating the replacement valve and otherinstruments introduced through passage 50.

As shown in FIG. 11B, an obturator 52 is positionable in passage 50 tofacilitate introduction of access cannula 22 through the chest wall.Obturator 52 has a tapered distal end 54, a proximal end 56, and a rim58 near proximal end 56 for engaging proximal end 46 of cannula body 44.Usually, obturator 52 is positioned in passage 50 of access cannula 22,and the two are introduced through a small incision formed in anintercostal space in the chest wall. Obturator 52 is then removed frompassage 50.

As described briefly above, access cannula 22 may further include asuture organizing ring 30 mounted to its proximal end 46. Sutureorganizing ring 30 has a ring-shaped body 60 and a plurality of slots 62circumferentially spaced about body 60. Usually, between 16 and 32 ofslots 62 are provided, depending upon the type of replacement valve andsuturing technique to be utilized in the procedure. An elastomericretaining ring 64 is disposed in a circumferential channel in ring body60, and has a plurality of slits 66, best seen in FIG. 11D, aligned witheach slot 62. Slits 66 are provided with chamfers 68 along the topsurface of retaining ring 64 to facilitate positioning sutures withinslits 66 for retention therein. The function of suture organizing ring30 will be described in greater detail below.

Referring again to FIG. 2, once access cannula 22 and trocar sleeves 24have been positioned in the patient's chest, endoscope 25 is introducedthrough trocar sleeve 24D and camera 26 is connected to video monitor 28(FIG. 1). Endoscope 25 is manipulated so as to provide a view of theright side of the heart, and particularly, a right side view of the leftatrium. Usually, an endoscope of the type having an articulated distalend, or a distal end disposed at an angle between 30° and 90° will beused, which is commercially available from, for example, Olympus Corp.,Medical Instruments Division, Lake Success, N.Y.

At this point in the procedure, if not previously accomplished, thepatient is placed on cardiopulmonary bypass (CPB), the patient's rightlung is at least partially collapsed, and the patient's heart isarrested. Suitable techniques for arresting cardiac function andestablishing CPB without a thoracotomy are described incommonly-assigned, applications Ser. No. 07/991,188, filed Dec. 15,1992, now abandoned, Ser. No. 08/123,411, filed Sep. 17, 1993, nowabandoned, Ser. No. 08/159,815, filed Nov. 30, 1993, now U.S. Pat. No.5,433,700, Ser. No. 08/162,742, filed Dec. 3, 1993, now abandoned andSer. No. 08/310,818, filed Jul. 28, 1994, now abandoned, all of whichare incorporated herein by reference.

As illustrated in FIG. 3, CPB is established by introducing a venouscannula 70 into a femoral vein 72 in patient P and advancing venouscannula 72 into the inferior vena cava 74 and/or into the interior ofheart H to withdraw deoxygenated blood therefrom. Venous cannula 70 isconnected to a cardiopulmonary bypass system 76 which receives thewithdrawn blood, oxygenates the blood, and returns the oxygenated bloodto an arterial return cannula 78 positioned in a femoral artery 80.

A pulmonary venting catheter 79 may also be utilized to withdraw bloodfrom the pulmonary trunk 77. Pulmonary venting catheter 79 may beintroduced from the neck through the interior jugular vein 106 or asubclavian vein and through superior vena cava 108, or from the grointhrough femoral vein 72 and inferior vena cava 74. Usually, a Swan-Ganzcatheter (not shown) is first introduced and positioned in pulmonaryartery 77 using well-known techniques, and pulmonary venting catheter 79is then introduced over the Swan-Ganz catheter. Blood is withdrawn frompulmonary trunk 77 through a port at the distal end of pulmonary ventingcatheter 79 and an inner lumen extending through the catheter outside ofthe patient's body. Pulmonary venting catheter 79 may further have oneor more balloons 81 at its distal end proximal to the distal port foroccluding pulmonary trunk 77.

An alternative method of venting blood from pulmonary trunk 77 isdescribed in U.S. Pat. No. 4,889,137, which is incorporated herein byreference. In the technique described therein, a catheter is positionedfrom the interior jugular vein in the neck through the right atrium,right ventricle, and pulmonary valve into the pulmonary artery 77. Thecatheter has a coil about its periphery which holds the pulmonary valveopen so as to drain blood from pulmonary trunk 77, thereby decompressingthe left side of the heart.

For purposes of arresting cardiac function, an aortic occlusion catheter82 is positioned in a femoral artery 84 by a percutaneous technique suchas the Seldinger technique, or through a surgical cut-down 86. Theaortic occlusion catheter 82 is advanced, usually over a guidewire (notshown), until an occlusion balloon 88 at its distal end is disposed inthe ascending aorta 90 between the coronary ostia 92 and thebrachiocephalic artery 94. Blood may be vented from ascending aorta 90through a port 95 at the distal end of the aortic occlusion catheter 82in communication with an inner lumen in aortic occlusion catheter 82,through which blood may flow to proximal end 96 of catheter 82. Theblood may then be directed to a blood filter/recovery system 98 toremove emboli, and then returned to the patient's arterial system viaCPB system 76.

When it is desired to arrest cardiac function, occlusion balloon 88 isinflated by injecting inflation fluid, usually a mixture of saline and aradiographic contrast agent, from a syringe 100 connected to proximalend 96 of catheter 82, through an inflation lumen in catheter 82 to theinterior of occlusion balloon 88. Occlusion balloon 88 is expanded untilit completely occludes ascending aorta 92, blocking blood flowtherethrough. A cardioplegic fluid such as potassium chloride (KCl) isthen delivered to the myocardium in one or both of two ways.Cardioplegic fluid may be delivered in an anterograde manner from acardioplegia pump 101 through an inner lumen in aortic occlusioncatheter 82 and a port distal to occlusion balloon 88 into the ascendingaorta upstream of occlusion balloon 88. Pressure in the aortic root ismeasured by a pressure measurement device 103 in communication with apressure lumen in catheter 82 having an opening distal to occlusionballoon 88. The cardioplegic fluid is then infused into the coronaryarteries and paralyzes the myocardium.

Alternatively, or in conjunction with such anterograde delivery,cardioplegic fluid may be delivered in a retrograde manner through aretroperfusion catheter 102 positioned in the coronary sinus 104.Retroperfusion catheter 102 may be positioned, usually over a guidewire(not shown), from the neck through the interior jugular vein 106 andsuperior vena cava 108, or from the groin through a femoral vein 72 andthe inferior vena cava 74. Retroperfusion catheter 102 may have one ormore balloons (not shown) at its distal end to enhance positioning andinfusion of cardioplegia into the coronary sinus. Cardioplegic fluid maythus be infused through the coronary veins into the capillary beds,paralyzing the myocardium.

In a preferred embodiment, the cardioplegic fluid consists of an aqueousKCl solution mixed with oxygenated blood at a ratio of four parts bloodto one part KCl solution. The aqueous KCl solution consists ofcrystalloid KCl mixed with saline to have a concentration in the rangeof 10-50 mEq K⁺/liter, preferably 15-30 mEq K⁺/liter. A cooler such asan ice bath (not shown) is used to cool the cardioplegic fluid to e.g.3° C.-10° C., so as to maintain the heart at a low temperature and tominimize demand for oxygen. This is usually accomplished withoutapplying external cooling to the heart as is generally applied inconventional open cardiac procedures. The cardioplegic fluid is infusedinto the ascending aorta through an opening at the distal end ofocclusion catheter 82 to maintain a pressure in the aortic root distalto the occlusion balloon sufficient to induce flow of fluid into thecoronary arteries through the coronary ostia. A pressure of about 60-80mmHg as measured through a pressure lumen in catheter 82 is usuallysufficient. Cardioplegic fluid is preferably delivered at a flowrate ofabout 250-350 ml/min. so as to deliver a total volume of 750-1000 ml inabout 2-4 minutes, although this may vary depending upon patientanatomy, physiological changes such as coronary dilation, and otherfactors. In pumping the cardioplegic fluid through the lumen in catheter82, the fluid should be subject to a pump pressure of no more than about300 mmHg to minimize damage to the blood component of the mixture. Heartcontractions will then cease, with circulation to the remainder of thepatient's body maintained by the CPB system. Cardioplegic fluid flow tothe patient's myocardium is maintained on a periodic basis, e.g., aboutevery 10-20 minutes for 2-4 minutes, so long as the myocardium is toremain paralyzed. A comprehensive description of cardioplegic techniquessuitable for use in the method of the invention is found in Buckberg,Strategies and logic of cardioplegic delivery to prevent, avoid, andreverse ischemic and reperfusion damage, J. Thorac. Cardiovasc. Surg.1987;93:127-39.

In addition to or instead of infusion of the blood/crystalloidcardioplegic solution, other techniques may be used to arrest heartcontractions. A more concentrated crystalloid KCl solution not mixedwith blood may be delivered through a lumen in occlusion catheter 82 athigher pressures than with a blood cardioplegic fluid mixture, sincewithout blood in the solution. there is no risk of hemolysis. Thisallows the inner lumen (as well as the overall catheter shaft) to be ofsmaller cross-sectional area while still providing the necessaryflowrate of fluid into the aortic root. However, the above bloodcardioplegia technique is presently preferred because it is generallybelieved to provide greater myocardial protection. In anotheralternative technique, the patient's body may be cooled in acold-temperature environment or by application of cold-packs to thechest to reduce the temperature of the myocardium sufficiently to inducefibrillation. The myocardium may be cooled directly by infusion of coldfluid such as cold blood or saline through the coronary arteries.Alternatively, electrical fibrillation may be accomplished by deliveringelectrical signals to the myocardium by means of electrodes placed onthe exterior surface of the heart or externally on the chest. However,cardiac arrest by means of fibrillation is generally less desirable thanchemical cardioplegic paralysis because there remains some degree ofheart motion which could make surgical intervention more difficult andbecause there is a significantly higher demand for oxygen, reducing thesafety and duration of the procedure.

The right lung may be collapsed using known techniques. Usually, a tubeis introduced through the trachea into the right main stem bronchus, anda vacuum is applied through the tube to collapse the lung.

Periodically during the procedure, it may be necessary to decompress theleft side of the heart by removing blood and other fluids which haveaccumulated in the aortic root, left atrium and/or left ventricle andwhich have not been removed by the pulmonary artery venting catheter (ifutilized). To remove such fluids, suction may be applied through aninner lumen in occlusion catheter 82 so as to aspirate fluids from theaorta, left ventricle, and or left atrium upstream of occlusion balloon88. Aortic root pressure may be monitored by pressure measurement device103 via a separate lumen in catheter 82. Such venting is usuallyperformed after each periodic infusion of cardioplegic fluid andadditionally as necessary to maintain decompression of the left side ofthe heart. In some cases, venting through occlusion catheter 82 may besufficient to maintain left heart decompression throughout theprocedure, eliminating the need for a pulmonary artery venting catheter.

Additional exemplary embodiments of an endovascular aortic partitioningsystem according to the invention are illustrated in FIGS. 26-34. Theheart 410 of FIGS. 26 and 27 is positioned in the living body of apatient and is accessed percutaneously.

In order to induce cardioplegia in the heart while maintaining thepatient it is necessary to divert the patient's blood circulationthrough an extracorporeal cardiopulmonary by-pass system. This isachieved by isolating the heart 410 on both the venous and arterialsides using appropriate percutaneously inserted venous catheter 411,aortic balloon catheter 412, and if this catheter 412 doesn't haveprovision for arterial blood return, arterial catheter 439 (see FIG.28). The venous outflow and arterial inflow lumina of the catheters 411and 412 of the by-pass system are of sufficient cross sectional area toachieve standard blood flows to maintain the patient's systemiccirculation during the period of extracorporeal circulation.

In the case of the use of a single venous double-ballooned catheter 411,as is shown in FIG. 26, the catheter 411 is inserted through the femoralvein preferably. A suitable guide wire is initially inserted and thecatheter 411 is then introduced in known manner under fluoroscopicguidance. The catheter 411 includes a pair of separately inflatableballoons 414 and 415 each connected to a balloon inflation controldevice (not shown) through suitable lumina in the catheter 411. Theballoon 414 is adapted to occlude the superior vena cavae 416 while theballoon 415 is adapted to occlude the suprahepatic inferior vena cavae417. A blood withdrawal lumen in the catheter 411 has an inlet orifice418 flush with the balloon 414, to avoid venous collapse during bloodflow into the catheter 411, and a series of inlet slots 419 in theinferior vena cavae. Blood drawn into the inlets 418 and 419 enters acommon single lumen. Blood drawn into the by-pass system through thecatheter 411 is oxygenated and returned to the patient in a manner whichwill be hereinafter described.

A separate lumen in the catheter 411 opens into the right atrium 422through aperture 421 to allow evacuation of blood from the right heartand the infusion of saline to induce topical cooling and/or to improvevisual acuity within the right heart.

In use, after the catheter 411 has been positioned the balloons may beinflated or deflated to vary the rate of venous return to the rightatrium 422 and therefore the degree of decompression of the left heart.Venous drainage may be effected by gravitational drainage or by applyinga degree of negative pressure to assist flow into the pump oxygenator.It will be appreciated that the distance between the balloons 414 and415 will need to be correct for a given patient and this may be assessedby X-ray examination to allow selection of an appropriately sizedcatheter. Alternatively separate catheters 411 b and 411 c could beused, as is shown in FIG. 34a, for the inferior and superior vena cavae,the cannula 411 b being introduced as has been described above and thecannula 411 c being introduced through the jugular or subclavian vein.It will also be appreciated that for simple operations not requiringcomplete occlusion of the right atrium it is possible to merely insert asimple catheter 411 into the right atrium to draw blood into the by-passsystem as is seen in FIG. 27. Positioning under fluoroscopic guidance isnot essential in this case.

The catheter 412 is positioned in the manner described above with itsfree end located in the ascending aorta 423. The catheter 412 is sopositioned by insertion preferably through the femoral artery 424 andvia the descending aorta 425 as is seen in FIG. 28.

If desired a fluoroscopic dye may be introduced into the aortic root 426through the catheter 412 for accurate positioning of the tip of thecatheter 412 relative to the aortic root 426 and the coronary ostia.

The catheter 412 carries at its free end a balloon 427. The balloon 427is arranged to be inflated with saline from an inflation control device428 of known type through a lumen in the catheter 412. The device 428 isfitted with a pressure gauge 429 to allow the operator to control theinflation of the balloon 427. The pressure of the fully inflated balloon427 should be of the order of 350 mmHg so as to be sufficient toeffectively occlude the aorta and to prevent the balloon moving whilenot being so great as to cause damage to the aortic wall. The balloon427 should have a maximum diameter sufficient to occlude the aorta andfor this purpose the maximum diameter should be about 35 mm. The balloon427 should have a length of about 40 mm so as not to be so long as toocclude or impede blood flow to the coronary arteries or to thebrachiocephalic, subclavian or carotid arteries. If necessary in anygiven patient the required length and diameter of the balloon may bedetermined by angiographic, X-ray examination or echocardiography and anappropriately sized catheter selected on that basis.

The balloon 427 is preferably connected to the lumen 432 through whichit is inflated at the end of the balloon 427 distal to the tip of thecatheter 412 through orifice 431 (see FIG. 30). This allows the tip ofthe catheter to contain fewer lumina than the remainder of the catheter.Accommodation of the deflated balloon around the tip of the catheter isthus possible without adding to the diameter of the tip as compared withthe rest of the catheter 412.

The catheter 412 includes a plurality of lumina (see FIGS. 31 and 32).In addition to the balloon inflation lumen 432 there is at least asingle venting/cardioplegia lumen 433 of circular cross-section. Theremay be a separate and extra circular lumen 434 for instrumentation. Iftwo lumens are present the venting/cardioplegia lumen may be circular orcrescent shaped in cross-section (FIGS. 31a, 31 b). The diameter of thevarious lumina should be as small as practicable commensurate with theintended use. In addition, there may be a continuous lumen 435 throughwhich arterial blood is returned from the by-pass. This may flow out ofthe catheter 412 through an orifice in the region of the external iliacartery. In alternative embodiments of the invention such as shown inFIGS. 28 and 33b the arterial return lumen 435 may comprise its owncatheter 439 of known type introduced into the other femoral artery orsome other suitable artery.

In use the catheter 412 is introduced percutaneously by puncture orcutdown as has been described and once blood flow through the by-pass isestablished (including systemic cooling) flows are reduced and theballoon 425 is inflated. Flows are then returned to the operating levelsand a suitable cardioplegic agent is introduced into the aortic root.Once the full volume of cardioplegic agent has been given and cardiacarrest achieved, the lumen is then used to vent the heart. Venting ofthe left ventricle may be effected by providing an extended cannula 438projecting from lumen 433 into the left ventricle (see FIG. 27) or bysimply applying negative pressure to the venting lumen 433 of the aorticcatheter. The heart may then be operated on or examined by insertion ofinstrumentation 437 such as a cardioscope or a laser into the heartthrough the lumen 434 or through atrial trocars. Alternatively, with theheart on by-pass as described above the heart can be approached by anopen method by an incision other than median sternotomy.

With cardiopulmonary bypass established, cardiac function arrested, andthe right lung collapsed, the patient is prepared for surgicalintervention within the heart H. A preferred technique of mitral valvereplacement will be described in detail here. Referring again to FIG. 2,a surgical cutting instrument such as angled scissors 110, as well as agrasping instrument such as grasping forceps 112, are introduced throughaccess cannula 22 or through trocar sleeves 24A, 24B. Angled scissors110 and forceps 112 are used to form an opening in the pericardium,providing access to the right side of the left atrium.

Angled scissors 110 are illustrated more clearly in FIGS. 12A-12D.Angled scissors 110 include a shaft 114 having a distal end 116, aproximal end 118, and an actuator 120 attached to proximal end 118.Shaft 114 of angled scissors 110 has a length selected to allowintervention within left atrium LA of heart H, and is usually at leastabout 15 cm in length and preferably 20 cm to 35 cm in length. Actuator120 includes a movable arm 122 pivotally coupled to a stationary arm124. A linkage 126 connects movable arm 122 to a push rod 128 extendingslidably through shaft 110. By pivoting movable arm 122 toward shaft114, push rod 128 is translated distally. A stationary blade 130 ismounted to distal end 116 of shaft 114, and a movable blade 132 ispivotally mounted to stationary blade 130. Push rod 128 is linked tomovable blade 132 such that distal movement of push rod 128 pivotsmovable blade 132 toward stationary blade 130. Blades 130, 132 may bemounted at various angles relative to shaft 114. as illustrated in FIGS.12B-12D. A flush port (not shown) may also be provided in shaft 114 fordelivering a flushing solution such as saline to distal end 116 toremove fluid and/or debris from blades 130, 132 or from the surgicalsite.

In addition to angled scissors 110, a retractable knife 134, illustratedin FIG. 13, may be used for various cutting purposes. Retractable knife134 comprises a shaft 136 having a distal end 138 and a proximal end140. A handle 142 is attached to proximal end 140, to which an actuator144 is slidably mounted. A push rod (not shown) is coupled to actuator144 and extends slidably through shaft 136. A knife blade 146 isslidably mounted at distal end 138 of shaft 136 and is linked to thepush rod, such that sliding actuator 144 proximally retracts knife blade146 within a sheath 148 mounted to distal end 138. Alternatively, knifeblade 146 may be fixed to shaft 136, and sheath 148 slidably mounted toshaft 136 and linked to the push rod, such that sheath 148 may beretracted and extended over knife blade 146 by sliding actuator 144.

Grasping forceps 112 are illustrated in FIGS. 14A-14B. Grasping forceps112 have a construction much the same as that of angled scissors 110,with an actuator 150 translating a push rod 152 slidably disposed in ashaft 154. A stationary jaw 158 is fixed to a distal end 156 of shaft154, and a movable jaw 160 is slidably mounted to shaft 154. Push rod152 is linked to movable jaw 160, such that translation of push rod 152by actuator 150 closes movable jaw 160 against stationary jaw 158.Grooves or other textural features may be provided on the inner surfacesof jaw 158 and/or jaw 160 to improve grip upon tissue.

FIG. 4 illustrates the view into the thoracic cavity through passage 50of access cannula 22. Angled scissors 110 aided by grasping forceps 112are shown cutting through the right side of left atrium LA to form anatriotomy 162. Atriotomy 162 is formed along dotted line 164 anterior toright pulmonary veins PV. A completed description of techniques forforming such an atriotomy is found in Kirklin and Barratt-Boyes, CardiacSurgery, pp. 329-340, the disclosure of which has been incorporatedherein by reference. Usually. atriotomy 162 will be formed undervisualization by means of endoscope 25 (FIGS. 1 and 2), although directviewing is possible through passage 50 of access cannula 22, or througha trocar sleeve 24.

Upon completion of atriotomy 162. the wall of left atrium LA on theanterior side of atriotomy 162 is retracted anteriorly by means ofthoracoscopic retractor 40, as illustrated FIGS. 1 and 5. Thoracoscopicretractor 40, illustrated more clearly in FIG. 15, includes a shaft 166having a distal end 168, a proximal end 170, and an inner lumen 172therebetween. A pair of finger rings 174 is mounted to proximal end 170of shaft 166. A guide 175 is also mounted to proximal end 170 having achannel 176 extending therethrough. A sliding rod 178 extends throughchannel 176 and has a plurality of teeth 180 on a lateral surfacethereof which are engaged by a pawl 182 pivotally mounted to guide 175and biased by a spring (not shown) against teeth 180. Sliding rod 178has a proximal end 184 to which a thumb ring 186 is attached, allowingthumb ring 186 to be drawn toward finger rings 174. A push rod 188 isslidably disposed in lumen 172 of shaft 166 and is attached at itsproximal end 190 to sliding rod 178. Three rake arms 192 are pivotallycoupled to shaft 166 within a transverse slot 194 at distal end 168.Rake arms 192 each have a hooked distal end 193 for engaging andretracting tissue. The distal end of push rod 188 slidably engages rakearms 192 within a slot 196 in each rake arm. In this way, by slidingpush rod 188 distally, rake arms 192 collapse in an overlappingconfiguration suitable for introduction through one of trocar sleeves24. Once rake arms 192 are introduced into the thoracic cavity, they maybe expanded by pulling thumb ring 186 relative to finger rings 174.

Referring again to FIG. 5, retractor 40 is introduced into the thoraciccavity through trocar sleeve 24 and rake arms 192 are deployed intotheir expanded configuration. Retractor 40 is manipulated so that hookedends 193 of rake arms 192 engage the wall of left atrium LA on theanterior side of atriotomy 162. Retractor 40 is then pulled in theanterior direction to retract the wall of left atrium LA, openingatriotomy 162 and exposing the patient's mitral valve MV within the leftatrium LA. A conventional stopcock, cam lock, or other clamping device(not shown) may be provided on trocar sleeve 24 to lock retractor 40 inposition, or shaft 166 may be provided with an adjustable collar (notshown) for engaging trocar sleeve 24 to maintain retractor 40 inposition.

It will be understood that retractor 40 illustrated in FIGS. 1, 5 and 15is merely exemplary of the various means that may be used for retractionof left atrium LA. Another suitable means of retraction is described inpublished European patent application number PCT/US92/06186, thecomplete disclosure of which is incorporated herein by reference. Thatapplication describes a clip which may be applied to tissue by means ofan introducer, and a flexible cable assembly attached to the clip whichmay be used to apply traction to the clip from outside of the patient'sbody. The clip may be applied to the wall of the left atrium LA on theanterior side of atriotomy 162 with the cable extending through a trocarsleeve 24, whereby atriotomy 162 is retracted open by applying tractionto the cable. The cable may be attached to the patient's body, to thesurgical drapes, or to another support structure outside of the body tomaintain the atriotomy open during the procedure. Alternatively, one ormore sutures (not shown) may be applied to the wall of left atrium LAanterior to atriotomy 162. The free ends of the sutures may be appliedto an internal structure in the thoracic cavity, or withdrawn from thethoracic cavity through a puncture or a trocar sleeve 24 and attached tothe patient's body or to the surgical drapes, thereby opening atriotomy162. Other suitable means of retraction include devices having acollapsible and expandable frame (not pictured) which is insertablewithin atriotomy 162. When deployed, the frame urges the opposing sidesof atriotomy 162 away from each other. and maintains the atriotomy openthroughout the procedure until the device is removed.

With atriotomy 162 retracted open, the interior of heart H is accessiblefor the performance of an interventional procedure therein. Instrumentsmay be introduced through access cannula 22 or trocar sleeves 24 andthrough atriotomy 162 to perform a procedure within left atrium LA.Additionally, such instruments may be extended through mitral valve MVinto the left ventricle, or from the left ventricle through the aorticvalve into the ascending aorta for inspection or intervention therein.In this way, the aortic valve may be repaired or replaced usingtechniques much like the mitral valve repair and replacement techniquesdescribed below.

When replacing mitral valve MV, it is often desirable to cut or removeall or a portion of the mitral valve leaflets VL. For this purpose,grasping forceps 112 may be used to grasp valve leaflet VL while angledscissors 110 and/or knife 134 are used to excise valve leaflet VL fromthe valve annulus VA. All or part of one or both valve leaflets VL maybe cut or removed in this way. When removing valve leaflets VL, however,it is generally desirable to avoid permanently cutting or removing thechordae tendonae and papillary muscles (not shown) attached to the leftventricle. It has been found that a patient's chordae tendonae andpapillary muscles may contribute to proper cardiac function even when apatient's natural valve has been replaced with a replacement valve.

At this point, it is usually necessary to size valve annulus VA so as toselect a replacement valve 36 of the proper size for patient P. Variousmeans may be used for sizing, but in one embodiment a sizing disk isintroduced through access cannula 22, and the diameter of the sizingdisk is compared to that of valve annulus VA. Preferred devices andmethods for sizing valve annulus VA are described more fully below.

Various types of replacement valves are available for replacement of themitral valve, and there are various ways of securing these replacementvalves within the patient's heart. One common means of replacement valveattachment is suturing the prosthesis to the patient's natural valveannulus. Referring to FIG. 6, after valve leaflets VL have been removed,a plurality of sutures 198 are applied to valve annulus VA, undervisualization by means of endoscope 25 (FIGS. 1-2) and/or by directvision through passage 50 of access cannula 22. Each end of each suture198 is attached to a curved needle 200. At least one and usually twoneedle drivers 202 are introduced into the thoracic cavity throughtrocar sleeves 24 and/or access cannula 22. A first of needle drivers202 is used to drive a tip of needle 200 through valve annulus VA, whilea second of needle drivers 202 is used to grasp the tip of needle 200and pull it completely through valve annulus VA. After being applied tovalve annulus VA, each suture 198 is withdrawn from the thoracic cavitythrough passage 50 of access cannula 22. and placed in one of slots 62in organizing ring 30. Because a needle 200 is attached to both ends ofeach suture 198, each needle 200 may be driven through valve annulus VAin a single direction. then withdrawn from the thoracic cavity throughpassage 50 of access cannula 22. Preferably, each suture 198 is cagedball type such as the Starr-Edwards valve (Baxter Healthcare Corp.,Edwards CVS Div., Irvine, Calif.), the tilting disk type such as theMedtronic Hall valve (Medtronic, Inc., Minneapolis, Minn.), theBjork-Shiley Monostrut valve (Shiley, Inc., Irvine, Calif.), theOmniscience® valve (Omniscience Medical Inc., Grove Heights, Minn.), aswell as the bileaflet type such as the St. Jude Medical valve (St. JudeMedical, Inc., St. Paul, Minn.), the Baxter Duromedics valve (BaxterHealthcare Corp., Edwards CVS Div., Irvine, Calif.), the Carbomedicsvalve (Carbomedics, Inc., Austin, Tex.), or the Sorin valve (SorinBiomedica, Saluggia, Italy). Bioprosthetic valves may be porcine aorticvalves such as the Hancock II bioprosthesis (Medtronic, Inc.,Minneapolis, Minn.), the Carpentier-Edwards supraannular bioprosthesis(Baxter Healthcare Corp., Edwards CVS Div., Irvine, Calif.), theCarpentier-Edwards stentless bioprosthesis (Baxter Healthcare Corp.,Edwards CVS Div., Irvine, Calif.), the St. Jude-Bioimplant bioprosthesis(St. Jude Medical, Inc., St. Paul, Minn.), or the Medtronic Intact®bioprosthesis (Medtronic, Inc., Minneapolis, Minn.), as well aspericardial valves such as the Mitroflow bioprosthesis (MitroflowInternational, Inc., Richmond, British Columbia, Canada), or theCarpentier-Edwards pericardial bioprostheses (Baxter Healthcare Corp.,Edwards CVS Div., Irvine, Calif.). The invention also facilitates valvereplacement with homografts and allografts, as well as with a variety ofreplacement valves not specifically listed here.

In an exemplary embodiment, the invention facilitates replacement of apatient's mitral valve with a mechanical bileaflet replacement valvesuch as the St. Jude Medical valve, illustrated in FIGS. 17A-17C. Inthis embodiment, replacement valve 36 comprises a ring-shaped frame 218and a pair of leaflets 220 pivotally mounted to frame 218. In the openconfiguration illustrated in FIGS. 17A-17B, leaflets 220 are nearlyparallel to each other, providing a flow passage 222 through which bloodmay flow in the direction of arrows 224. In the event of fluid pressureagainst the inner faces 226 of leaflets 220, leaflets 220 pivot into aclosed configuration, blocking flow passage 222. A sewing ring 228 isattached to frame 218 to which sutures 198 may be applied for securingreplacement valve 36 in the heart. positioned within a slit 66 inretaining ring 64 (FIGS. 11A-11D) to frictionally engage the suture andkeep it within slot 62.

Various types of stitches may be used in applying sutures 198 to valveannulus VA. In an exemplary embodiment, a “mattress” suture technique isused, wherein each needle 200 is driven through valve annulus VA fromthe ventricular side toward the atrial side of valve annulus VA.Alternatively, an “everting mattress” suture technique is used, whereineach needle 200 is driven through valve annulus VA from the atrial sidetoward the ventricular side of valve annulus VA. Various other types ofstitches may also be used, depending upon the type of replacement valveto be utilized and the position in which it is to be mounted to valveannulus VA.

FIGS. 16A-16B illustrate the construction of needle drivers 202 ingreater detail. Needle drivers 202 include a shaft 204 having a distalend 206 and a proximal end 208. An actuator 210 is attached to proximalend 208, and is constructed as described above in connection with FIG.12A. Actuator 210 translates a push rod 212 extending through shaft 204.A-stationary jaw 214 is fixed to distal end 206 of shaft 204, and amovable jaw 216 is pivotally mounted to stationary jaw 214. Movable jaw216 is linked to push rod 212, whereby distal movement of push rod 212closes movable jaw 216 against stationary jaw 214. Carbide surfaces aswell as grooves or other textural features may be provided on the innersurfaces of jaws 214, 216 to enhance gripping of needles 200. Further, alocking mechanism (not shown) may be included on actuator 210 to lockjaws 214, 216 in the closed position.

Referring to FIG. 7, once all of sutures 198 have been withdrawn fromthe thoracic cavity and placed in slots 62 of organizing ring 30, thesutures are applied to replacement valve 36, held in position byintroducer 38. Replacement valve 36 may be any of a variety ofcommercially available prostheses, including mechanical andbioprosthetic, stented and unstented, as described in Bodnar and Frater,Replacement Cardiac Valves, pp. 4-7, which has been incorporated hereinby reference, and in Jamieson, “Modern Cardiac ValveDevices—Bioprostheses and Mechanical Prostheses: State of the Art,” J.Card. Surg. 8:89-98 (1993). Mechanical valves may be of the Asillustrated in FIGS. 17B-17C, replacement valve 36 may be mounted tointroducer 38 for introduction into the heart through passage 50 ofaccess cannula 22. Replacement valve 36 may have various sizes accordingto the size of the mitral valve being replaced. However, the outerdiameter of sewing ring 228 is usually about 19 mm to 35 mm, which, formost adult patients, is larger than the width of the third, fourth,fifth or sixth intercostal spaces, which range from 15 mm to 20 mm inwidth. The height of replacement valve 36, on the other hand, is smallerthan the width of these intercostal spaces, usually being about 8 mm to15 mm. Therefore, passage 50 is configured to allow replacement valve 36to pass through it in an edge-first orientation, as illustrated in FIG.17C.

Introducer 38 will now be described with reference to FIGS. 18-20.Introducer 38 includes a shaft 230 having a distal end 232, a proximalend 234, and an inner lumen 236 therebetween. Shaft 230 has a lengthselected to allow placement of replacement valve 36 in the mitral valveposition within the patient's heart from outside of the patient'sthoracic cavity, and is usually at least about 20 cm in length, andpreferably about 25 cm to 35 cm in length. A handle 238 is attached toproximal end 234, and a rotatable knob 240 is mounted to handle 238 forpivoting the replacement valve 36 relative to shaft 230. A pull ring 242extends proximally from pivot knob 240 for releasing replacement valve36 from introducer 38. As best seen in FIGS. 20A-20B, push rod 244extends through inner lumen 236, and is coupled at its distal end 248 toa pivot 250 which is pivotally mounted within a slot 252 at distal end232 of shaft 230. A shank 254 extends distally from pivot 250 and hasthreads or other means for attachment to a valve holder 255 forreplacement valve 36. Knob 240 is fixed to a threaded shaft 256 receivedwithin a threaded bore 258 in handle 238, whereby rotation of knob 240translates threaded shaft 256 distally or proximally, depending upon thedirection of rotation. Push rod 244 has a proximal end 260 which engagesa distal end 262 of threaded shaft 256. A spring 264 biases push rod 244in a proximal direction against distal end 262. In this way, rotation ofknob 240 pulls or pushes push rod 244, thereby pivoting pivot 250 suchthat shank 254 extends either distally or laterally.

Referring to FIGS. 19A-19G, valve holder 255 includes a stationary arm266 attached to shank 254, and a movable arm 268 pivotally mounted tostationary arm 266. Each of arms 266, 268 has an annular channel 270configured to engage frame 218 of replacement valve 36 within flowchannel 222 (FIG. 17A). Arms 266, 268 are further dimensioned andconfigured for introduction through passage 50 of access cannula 22 whenreplacement valve 36 is held in channels 270. As illustrated in FIG.19A, when attached to shank 254 on introducer 38, valve holder 255 maybe pivoted in the direction of arrow 272 by rotation of knob 240. Inthis way, the replacement valve 36 held by holder 255 may be introducededge-first through passage 50 in access cannula 22, then pivotedapproximately 90° to an orientation suitable for attachment in themitral valve position within heart H.

To facilitate releasing replacement valve 36 from holder 55 from alocation outside of the patient's body, a pull wire 274 is coupled tomovable arm 268 by, for example, an anchor ball 276 disposed within anaperture 278 (see FIG. 20A). Pull wire 274 extends through an innerlumen (not shown) in push rod 244, and is attached at its proximal end280 to pull ring 242. A spring 282 within an aperture 284 in knob 240biases pull ring 242 in a distal direction. In this way, pulling on pullring 242 pivots movable arm 268 as shown in FIG. 19C, allowingreplacement valve 36 to be removed from channels 270. Anchor ball 276and/or pull ring 242 may be configured so as to be removable from pullwire 244, allowing valve holder 255 to be removed from introducer 38 bydecoupling arm 266 from shank 254.

In order to keep replacement valve 36 on holder 255 when holder 255 isnot attached to introducer 38, a pair of holes 286 are provided in arm266 in alignment with a corresponding pair of holes 288 in arm 268. Whenreplacement valve 36 has been placed on holder 255, a suture (not shown)may be tied through holes 286, 288 to prevent pivoting of arm 268,thereby retaining replacement valve 36 on holder 255. Once holder 255has been attached to introducer 38, the suture may be removed, allowingarm 268 to pivot in response to rotation of knob 240.

It will frequently be desirable for valve holder 255 and replacementvalve 36 to be pre-assembled, sterilized, and packaged together in asingle sterile pack. In this way, upon opening the sterile pack in theoperating room, the replacement valve 36 and holder 255 are ready forimmediate surgical use. Further, it may be desirable for introducer 38to be sterilized with replacement valve 36 and included in the samesterile pack. In such cases, holder 255 may be integrated with andnon-removable from introducer 38, with replacement valve 36 beingmounted to arms 266, 268 at the distal end of introducer 38 within thesterile pack. Alternatively, introducer 38 may be a reusable devicewhich is attached to holder 255 and replacement valve 36 in theoperating room at the time of the procedure.

As mentioned above, in order to select a replacement valve 36 which isof the appropriate size for patient P, valve annulus VA is usually sizedprior to applying sutures 198 to valve annulus VA. Sizing may beaccomplished in various ways, but in an exemplary embodiment, isperformed by means of a sizing disk 290, illustrated in FIGS. 21-23,pivotally attached to introducer 38. Sizing disk 290 may be pivotedapproximately 90° relative to shaft 230 of introducer 38, from anedge-first orientation suitable for introduction through access cannula22, to a face-first orientation suitable for sizing valve annulus VA. Asshown in FIGS. 22 and 23, sizing disk 290 is configured for attachmentto shank 254 of introducer 38, preferably by means of a threaded hole292. A notch 294 is provided in a proximal portion of disk 290 throughwhich distal end 232 of shaft 230 may extend when disk 290 is in theedge-first orientation. An aperture 296 is disposed in the middle ofdisk 290 through which distal end 232 of shaft 230 may extend when disk290 is in the face-first orientation. Preferably, a plurality ofinterchangeable sizing disks 290 of various diameters are provided forthe procedure, allowing various sizing disks 290 to be introduced intoheart H and compared with valve annulus VA until the diameter of thesizing disk corresponds to that of valve annulus VA.

In place of sizing disk 290, an expandable balloon or basket may be usedfor sizing valve annulus VA. Fluoroscopy, transesophagealechocardiography (TEE), epicardial or trans-thoracic ultra-sonography.or angiography may also be used to facilitate sizing valve annulus VA.

When the size of valve annulus VA has been identified, sizing disk 290may be removed from introducer 38 and replaced by a replacement valve 36of the appropriate size, mounted on holder 255. Introducer 38 may thenbe clamped to support stand 34 with replacement valve 36 positionedbetween first organizing ring 30 and second organizing ring 32, asillustrated in FIG. 7.

Sutures 198 are applied to replacement valve 36 by passing needles 200through sewing ring 228 using needle drivers 202. Sutures 198 are thenpositioned in circumferentially spaced positions on second organizingring 32. Second organizing ring 32 comprises, as illustrated in FIGS.24A-24C, an inner ring 298 fixed to support stand 34, and an outer ring300 rotatably mounted to inner ring 298. An elastomeric retaining ring302 is disposed in an annular channel 304 in inner ring 298. Radial pins303 are fixed to inner ring 298 and extend through slots 305 in outerring 300, thereby limiting the rotation of outer ring 300 relative toinner ring 298. A plurality of slots 306 are disposed incircumferentially spaced positions about inner ring 298, and acorresponding number of slots 308 alignable with slots 306 are disposedin outer ring 300. Retaining ring 302 has a plurality of slits 310 whichare aligned with slots 306 in inner ring 298. A clamp 312 for clampingshaft 230 of introducer 38 is disposed on an extension 314 fixed tosupport stand 34.

After being applied to replacement valve 36, sutures 198 may bepositioned within inner slots 306, slits 310, and outer slots 308. Onceall of sutures 298 have been applied to replacement valve 36 andpositioned in organizing ring 32, outer ring 300 may be rotated relativeto inner ring 298. thereby locking sutures 298 in position.

Referring now to FIG. 8A, replacement valve 36 may then be introducedinto the left atrium LA by advancing introducer 38 through passage 50 ofaccess cannula 22. Replacement valve 36 is oriented on introducer 38 soas to be introduced edge-first through passage 50. As replacement valve36 is advanced into the thoracic cavity, organizing ring 32 maintainstension on sutures 198, allowing replacement valve 36 to slide alongsutures 198. Introducer 38 is advanced through atriotomy 162 so thatreplacement valve 36 is disposed within left atrium LA. Replacementvalve 36 is then pivoted on introducer 38 by rotating knob 240, so thatsewing ring 228 of replacement valve 36 (FIG. 17A) may be aligned withvalve annulus VA.

Introducer 38 is then advanced further into left atrium LA so as toposition replacement valve 36 against or within valve annulus VA, asillustrated in FIG. 8B. Square or overhand knots are then formed insutures 198 outside of the patient's thoracic cavity, and the knots arepushed by a knot pusher 316 through passage 50 and atriotomy 162 towardsewing ring 228 of replacement valve 36.

While knot pusher 316 may have a variety of configurations, an exemplaryembodiment is illustrated in FIGS. 25A-25B. Knot pusher 316 comprises ashaft 318 having a distal end 320 and a proximal end 322, to which isconnected an actuator 324 constructed like actuator 120 described abovein connection with FIG. 12A. Actuator 324 translates a push rod 326extending through shaft 318. A pair of movable jaws 328 are pivotallymounted to distal end 320 of shaft 318, and are coupled to push rod 326such that proximal movement of push rod 326 opens jaws 328. A notch 330at the distal end of each jaw 328 is configured to receive a suture 198.

In use, a first free end of a suture 198 is tied in a loop or slip knotover a second free end of suture 198, and jaws 328 are positioned justproximal to the knot. Jaws 328 are then opened such that each free endof suture 198 is positioned within a notch 330 at the distal end of jaws328 and the slip knot is disposed centrally between jaws 328. Whileholding tension on the free ends of the sutures outside the thoraciccavity, knot pusher 316 is advanced distally, pushing the slip knotthrough passage 50 of access cannula 22 and atriotomy 162 until the slipknot engages sewing ring 228 of replacement valve 36.

Referring now to FIG. 9, when a plurality of knots 332 (usually 5 to 8)have been tied and pushed against sewing ring 228 by knot pusher 316,knots 332 are cinched down tightly, and free ends 334 are trimmed usingscissors 110 or other cutting device.

It will be understood to those of ordinary skill in the art that thethoracoscopic devices and methods disclosed above for tissuemanipulation, retraction, cutting, suturing, and the like may be used toaccomplish procedures such as annuloplasty, commissurotomy, quadrangularresection, shortening and reattachment of chordae tendonae, and variousother valve repair procedures. To perform annuloplasty, valve annulus VAis contracted by suturing a portion of the valve annulus so as tooverlap an adjacent portion, or by attaching a prosthetic annuloplastydevice such as a Carpentier or Duran annuloplasty ring (not shown) tovalve annulus VA to reduce its diameter. To perform commissurotomy, thevalve leaflets VL are separated by cutting between them where they havefused together due to calcification or disease. To perform quandrangularresection, valve leaflets VL are shortened or narrowed by excising aportion of one or more leaflets VL, and reattaching the remainingportions of the leaflet by suturing. The chordae tendonae (not shown),which act as resilient springs between valve leaflets VL and thepapillary muscles (not shown) attached to the heart wall in the leftventricle LV, may be shortened by excising a portion thereof andreattaching the ends of the remaining portions by suturing. Similarly,severed chordae tendonae may be restored by reattachment of the severedends with sutures. Open-chest techniques for performing such proceduresare described in detail in Kirklin and Barratt-Boyes, Cardiac Surgery,pp. 329-340, the disclosure of which has been incorporated herein byreference.

When the valve replacement or other surgical procedure in left atrium LAis completed, atriotomy 162 is closed. Sutures, thoracoscopic staples orother types of closure devices may be used for this purpose. In oneembodiment, illustrated in FIG. 10, atriotomy 162 is closed by suturing,wherein needle drivers 202 are introduced through trocar sleeves 24and/or access cannula 22, and a suture 336 having a needle 338 attachedto an end thereof is used to sew up atriotomy 162 using conventionalsuturing techniques. Before and/or during closure, a suction/irrigationtube (not shown) is usually introduced through a trocar sleeve 24 andinto left atrium LA or left ventricle LV to remove any air therein andto fill the heart chambers with a saline solution.

After atriotomy 162 has been closed, any remaining instruments areremoved from the thoracic cavity. A chest tube may be introduced throughone of trocar sleeves 24 to facilitate evacuation of the pleural cavity.Access cannula 22 and trocar sleeves 24 are then removed from the chestwall, and the incisions or penetrations through which they wereintroduced are closed, usually by suturing or stapling.

The patient's lung may then be reinflated, and cardiac function may berestarted. As described in copending application Ser. No. 07/991,188,which has been incorporated herein by reference, infusion ofcardioplegic fluid through aortic occlusion catheter 82 and/orretroperfusion catheter 102 is discontinued, and a saline solution isinfused through one or both of these catheters to irrigate the heart andcoronary arteries (see FIG. 3). The saline solution, along with blood,other fluids, air, thrombus, and other emboli within the heart orcoronary arteries are then aspirated through the inner lumen of aorticocclusion catheter 82, as well as through venous cannula 70 and/orpulmonary venting catheter 79. Occlusion balloon 88 on aortic occlusioncatheter 82 is then deflated, allowing warm, oxygenated blood to flowinto the coronary arteries to perfuse the myocardium. Cardiaccontractions will usually begin soon thereafter. In some cases,electrical defibrillation may be necessary to help restore cardiacfunction. Aortic occlusion catheter 82 and retroperfusion catheter 102may then be removed from the patient. Cardiopulmonary bypass is thendiscontinued, and arterial cannula 78, venous cannula 70, and pulmonaryventing catheter 79 are removed from the patient.

In addition to performing mitral valve repair and replacement, thetechniques of the invention also facilitate surgical intervention intoother regions of the heart and great vessels. The devices and methodsdescribed above may be used to form an opening directly into the leftventricle, right atrium, or right ventricle, or into a great vessel suchas the aorta, superior vena cava, inferior vena cava, pulmonary artery,or pulmonary vein, for surgical intervention in such cavities. Forexample, a penetration may be made in the wall of the aorta, and theaortic valve may be repaired or replaced with a prosthesis, usingtechniques and devices like those described above for mitral valvereplacement. Moreover, the devices and methods of the invention alsofacilitate intracardiac procedures such as repair of atrial orventricular septal defects, electrophysiological mapping and ablation ofthe myocardium, myocardial drilling, and other procedures. Furthermore,devices may be introduced through an opening into the heart or greatvessel and advanced therefrom into vessels such as the coronary arteriesto perform procedures such as angioplasty, atherectomy, coronary arterybypass grafting, or treatment of aneurysms.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention, which is defined by the appendedclaims.

What is claimed is:
 1. A method of closed-chest surgical interventionwithin an internal cavity of a patient's heart or great vessel, themethod comprising: establishing cardiopulmonary bypass; arresting thepatient's heart; viewing an internal portion of the patient's chestthrough a scope extending through a percutaneous intercostal penetrationin the patient's chest; forming an internal penetration in a wall of theheart or great vessel using cutting means introduced through apercutaneous intercostal penetration in the patient's chest; andintroducing an interventional tool through a percutaneous intercostalpenetration and through the internal penetration to perform a surgicalprocedure within the internal cavity under visualization by means ofsaid scope.
 2. The method of claim 1 wherein the patient's heart isarrested by occluding the patient's aorta between the patient's coronaryarteries and the patient's brachiocephalic artery with an expandablemember on a distal end of an endovascular catheter, and perfusing thepatient's myocardium with cardioplegic fluid.
 3. The method of claim 1wherein the interventional tool is introduced through a cannulapositioned in a percutaneous intercostal penetration.
 4. The method ofclaim 1 wherein the surgical procedure comprises surgically treating aheart valve.
 5. The method of claim 4 further comprising the step ofremoving at least a portion of the heart valve by means of a cuttingtool introduced through a percutaneous intercostal penetration-andthrough the internal penetration.
 6. The method of claim 4 furthercomprising the step of introducing a replacement valve through apercutaneous intercostal penetration and through the internalpenetration into the internal cavity.
 7. The method of claim 6 furthercomprising fastening the replacement valve within the internal cavity bymeans of an instrument introduced through a percutaneous intercostalpenetration and through the internal penetration.
 8. The method of claim6 wherein the replacement valve is introduced through a cannulapositioned in a percutaneous intercostal penetration.
 9. The method ofclaim 4 wherein a percutaneous intercostal penetration is created in aright lateral portion of the patient's chest.
 10. The method of claim 9wherein the internal penetration is made in a wall of the patient's leftatrium.
 11. The method of claim 10 wherein the heart valve comprises amitral valve.
 12. The method of claim 10 wherein the heart valvecomprises an aortic valve.
 13. A method of closed-chest replacement of aheart valve in a patient's heart, the method comprising: establishingcardiopulmonary bypass; arresting the patient's heart; viewing thepatient's heart through a scope extending through a percutaneousintercostal penetration in the patient'S chest; forming an internalpenetration through a wall of the patient's heart using a cutting toolintroduced through a percutaneous intercostal penetration in thepatient's chest; positioning a replacement valve through a percutaneousintercostal penetration in the patient's chest and through the internalpenetration into a chamber of the heart; and securing the replacementvalve in a valve position in the heart.
 14. The method of claim 13wherein the patient's heart is arrested by occluding the patient's aortabetween the patient's coronary arteries and the patient'sbrachiocephalic artery with an expandable member on a distal end of anendovascular catheter, and perfusing the patient's myocardium withcardioplegic fluid.
 15. The method of claim 13 wherein the heart valvecomprises a mitral valve, the valve position comprising a mitral valveposition.
 16. The method of claim 15 wherein the chamber comprises aleft atrium of the patient's heart.
 17. The method of claim 13 whereinthe percutaneous intercostal penetration is disposed in a right lateralportion of the patient's chest.
 18. The method of claim 13 furthercomprising the step of removing at least a portion of the patient'sheart valve using a cutting tool introduced through a percutaneousintercostal penetration and through the internal penetration.
 19. Themethod of claim 13 further comprising sizing the patient's heart valveby means of a sizing instrument introduced through a percutaneousintercostal penetration and through the internal penetration.